PEDIATRIC VIROTHERAPY: ONCOLYTIC PAROVIRUSES FOR THE TREATMENT OF MALIGNANT DISEASES OCCURRING IN CHILDHOOD AND ADOLESCENCE
Table of Contents
Our work is focused on the pre-clinical evaluation of the use of parvovirus H-1 as a novel therapeutic approach in pediatric oncology.
CURRENT RESEARCH PROJECTS
1. Systematic in vitro screening of the cytotoxic efficacy of H-1PV in pediatric tumor cells
To assess the potential benefit of pediatric patients from H-1V treatment a systematic, ongoing in vitro screening is performed. To date, it includes more than 30 pediatric medulloblastoma, glioblastoma, neuroblastoma, Ewing’s sarcoma and osteosarcoma cell lines.
2. Preclinical studies on the therapeutic efficacy of parvovirus H-1 (H-1PV) to brain tumor-initiating cells
Despite multi-modal treatment concepts including surgery, radiation, and chemotherapy malignant brain tumors are characterized by an extremely bad prognosis. Thus, pre-clinical and clinical research focuses on new therapeutic approaches, such as oncolytic virotherapy. Based on extensive pre-clinical studies in vitro and in vivo, a phase I/IIa clinical trial for the application of parvovirus H-1 in adult glioblastoma patients has been initiated in October 2011. In children medulloblastoma is the most frequent malignant brain tumor, with subgroups of high-risk patients suffering from extremely poor prognosis. Here, the stage of development is still at a pre-clinical level.
Clinical relapse of brain tumors has been hypothesized to originate from brain tumor-initiating cells resistant to conventional treatment. In order to assess the efficacy of H-1PV to induce oncolysis in recurrent brain tumors we systematically address this question using a panel of neurosphere cultures. These glioblastoma and medulloblastoma cultures were obtained from collaboration partners who established them from primary tumor material.One focus of our current research is to confirm that H-1PV is able to infect, to replicate in and to selectively kill brain tumor-initiating cells in vitro and in appropriate xenograft-bearing animal models and to elucidate the mechanisms which enable H-1PV to induce these effects.
3. Optimization strategies for the application of H-1PV in a clinical setting
Since the state of pre-clinical research is most advanced for neuroblastoma we use cell culture and animal models for high-risk neuroblastoma to
- optimize the mode of application of H-1PV
- further increase the therapeutic efficacy by identification of the most promising combination treatment approaches (cytostatic drugs, epi-genetic modulators)
- identify markers predictive for the response to parvovirotherapy
Confocal microscopy (60-fold magnification) of an anti-NS1 immunofluorescence staining of D238 medulloblastoma cells 24 hours after infection with wild type H-1PV per cell (red). Nuclear membranes were stained with anti-lamin beta (green). Colocalization is shown by merging the pictures (below).
FUTURE PROJECTS AND GOALS
Beyond the ongoing research projects described, we have started new projects in order to gain insights into the mechanisms of virus induced cytotoxicity to embryonic tumors of the nervous system and tumor- initiating cells derived thereof. In collaboration with the Division Pediatric Neurooncology (DKFZ) and the siRNA screening facility (Bioquant), we aim to characterize target genes of viral proteins inducing fatal dysregulations in the metabolism of these malignant cells using high throughput technologies such as expression analysis by microarrays and siRNA library screening.
Based on pre-clinical in vivo proof of concept experiments we aim in the preparation of a clinical phase I/IIa clinical trial on pediatric patients with primary progressive or recurrent embryonic tumors of the nervous system in the framework of cooperations with ORYX GmbH & Co. KG and the Department of Pediatric Oncology, Hematology, Immunology and Pulmonology, University Hospital Heidelberg.
ORYX GmBH & Co. KG
Deutsche Krebshilfe e. V.
Brigitte Schlieben-Lange Programm (Ministerium für Wissenschaft, Forschung und Kunst, Baden-Württemberg)
Dr. Holger Erfle, Bioquant, Heidelberg
Dr. Hedwig Deubzer, Dr. Till Milde, Inga Wiegand, Prof. Dr. Olaf Witt, Klinische Kooperationseinheit Pädiatrische Onkologie, DKFZ, Heidelberg
Prof. Dr. Christel Herold-Mende, Klinik für Neurochirurgie, Universitätsklinikum Heidelberg
Prof. Dr. Magnus von Knebel Doeberitz, Angewandte Tumorbiologie, Pathologisches Institut, Universitätsklinikum Heidelberg
Dr. Hendrik Witt, PD Dr. Stefan Pfister, Abteilung Pädiatrische Neuroonkologie, DKFZ, Heidelberg